Firstly are you playing through your TV? These can often add extra filters that can add a delay that you don't notice when just watching a movie. Most TV's will have some kind of 'Game Mode' that will turn off the filters, or in my case tell your TV that you have a PC plugged into that port.
Secondly, that graphics card is not great. Yeah a toaster can run Portal 2, but not with all the bells and whistles. Have you tried playing those games on lower settings?
Lastly, you didn't mention what CPU you have. This could be causing a bottleneck, especially in Shogun 2.